The relative lowering of vapour pressure of a dilute aqueous solution containing nonvolatile solute is 0.0125. The molality of the solution is about

• 0.70

• 0.50

• 0.90

• 0.80

92.

If the elevation in boiling point of a solution of 10g of solute (mol. wt. = 100) in 100g of water is ΔT_b,  the ebullioscopic constant of water is 

• 100T_b

• ΔT_b

• 10T_b

• 10

Dry air is passed through a solution containing 10 g of a solute in 90 g of water and then through pure water. The loss in weight of solution is 2.5 g and that-of pure solvent is 0.05 g. Calculate the molecular weight of the solute.

• 50

• 180

• 102

• 25

The van't Hoff factor of BaCl₂ at 0.01 M concentration is 1.98. The percentage of dissociation of BaCl₂ at this concentration is :

• 49

• 69

• 89

• 98

Which of the following make up an isotonic triad?

• ${}_{32}{}^{78}\mathrm{Ge}, {}_{33}{}^{77}\mathrm{As}, {}_{31}{}^{74}\mathrm{Ga}$

• ${}_{18}{}^{40}\mathrm{Ar}, {}_{19}{}^{40}\mathrm{K}, {}_{20}{}^{40}\mathrm{Ca}$

• ${}_6{}^{14}\mathrm{C}, {}_8{}^{16}\mathrm{O}, {}_7{}^{15}\mathrm{N}$

• ${}_6{}^{13}\mathrm{C}, {}_7{}^{12}\mathrm{C}, {}_7{}^{14}\mathrm{N}$

The statement "the relative lowering of the vapour pressure is equal to the ratio of the moles of the solute to the total number of the moles in the solution" refers to :

• Hess's law

• Dalton's law

• Raoult's law

• Charle's law

Ethylene glycol is added to water as antifreeze. It will :

• decrease the freezing point of water in the winter and increase the boiling point of water in the summer

• only decrease the freezing point of water

• only increase the boiling point of water

• be used for cleaning the radiator in a car

Which of the following 1 : 1 mixture will act as buffer solution ?

• HCl and NaOH

• CH₃COOH and CH₃COONa

• KOH and CH₃COOH

• CH₃COOH and NaCl

Identify the mixture that shows positive deviation from Raoult's law :

• CHCl₃ + (CH₃)₂CO

• (CH₃)₂CO + C₆H₅NH

• CHCl₃ + C₆H₆

• (CH₃)₂CO + CS₂

If ΔG for a reaction is negative, you infer that the change is : 

• spontaneous

• non-spontaneous

• reversible

• irreversible